1. Field of the Invention
The present invention relates to a cassette transfer apparatus for transferring a cassette incorporating an information storage medium therein to a desired position and for loading/unloading the cassette with reference to a given device.
2. Description of the Related Art
U.S. patent application Ser. No. 043,252, filed by the present applicant on Apr. 27, 1987, discloses an automatic disk cassette-changing apparatus employing a similar type of transfer apparatus to that provided by the present invention. The changing apparatus comprises an information processing device, and a storage section located adjacent to the information processing device and storing a number of optical disk cassettes. The transfer apparatus carries a cassette between the processing device and the storage section, and loads or unloads the cassette from the processing device or the storage section.
The transfer apparatus includes a cassette-holding portion therein, and a pair of endless belts movable along the respective edges of the holding portion. A pawl engageable with a cassette is fixed to each belt. A cassette can be taken from either the storage section or the processing device and set in the holding portion of the transfer apparatus by driving the belts in a predetermined direction, with their pawls engaged with the cassette, and can be loaded into the storage section or the processing device by driving the belts in the opposite direction to the above predetermined direction.
However, the transfer apparatus having the above construction has the problem that a cassette is likely to be disengaged from the pawls, due to flection of the belts or for some other causes, when it is being taken into the holding portion or taken out thereof. In this case, the cassette cannot be set in the holding portion or taken out thereof, so that an automatic cassette-changing operation with reference to the processing device becomes impossible to perform.
In addition, it may happen that the pawls of the belts will catch the cassette, preventing reliable engagement or disengagement of the cassette. In this case as well, the automatic cassette changing operation becomes impossible to perform.